Cell phone conversation and conversation with passengers have been shown to impair the driving performance of experienced adult drivers in simulator and on-road experiments by diverting attention away from the task of driving. Young, inexperienced drivers have more difficulty processing visual information that may be needed for safe driving. Therefore, competing mental tasks such as cell phone and driver-passenger conversations may impair inexperienced adolescent drivers even more than experienced adolescent and adult drivers. Accordingly, we propose to compare the effects of cell phone and driver passenger conversation on driving performance in 24 novice adolescent, 24 experienced adolescent, and 24 experienced young adult drivers using a high-fidelity driving simulator. We will examine driving performance of subjects under the following conditions: 1) driving only; 2) driving while conversing with a friend via cell phone; and 3) driving while conversing with a friend seated nearby (to mimic the role of a passenger). Results will inform policy decisions on toughening passenger restrictions and banning cell phone use in adolescent drivers.